Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cygnus |
Right ascension | 19h 24m 33.06773s [1] |
Declination | +50° 14′ 29.1263″ [1] |
Apparent magnitude (V) | 5.60 – 8.49 [2] |
Characteristics | |
Spectral type | M7IIIab + Be [3] |
Variable type | Z And and SR [2] |
Astrometry | |
Radial velocity (Rv) | −59.74 [4] km/s |
Proper motion (μ) | RA: −7.09 [1] mas/yr Dec.: −59.74 [1] mas/yr |
Parallax (π) | 5.4642 ± 0.2172 mas [5] |
Distance | 600 ± 20 ly (183 ± 7 pc) |
Orbit [6] | |
Period (P) | 15.58±0.13 yr |
Semi-major axis (a) | 8.5 AU |
Eccentricity (e) | 0.122±0.024 |
Inclination (i) | 84° |
Semi-amplitude (K1) (primary) | 4.45±0.12 km/s |
Details [6] | |
Red giant | |
Mass | 2 M☉ |
Radius | 280 R☉ |
Luminosity | 5012 L☉ |
Temperature | 3,100 K |
White dwarf | |
Mass | 0.7 M☉ |
Luminosity | 0.25 L☉ |
Other designations | |
Database references | |
SIMBAD | data |
CH Cygni (CH Cyg / HIP 95413 / BD +49 2999) is a red giant, variable, symbiotic binary in the constellation Cygnus. It is the nearest symbiotic star to Earth, and one of the brightest, making it an ideal candidate for study.
CH Cygni has a mass of 2 M☉ and a radius of 280 R☉. Its white-dwarf companion has a mass of 0.75 M☉, and the orbital period of the two stars is 5689 days. [6] CH Cygni is classified as M7IIIab + Be. [3]
The earliest observations of CH Cygni were made in 1890 by Pickering and Wendel using wedge photometer, and was classified as a M6III variable star in 1924. [8] In 1963 strong H I emissions were observed, indicating CH Cygni was likely in a symbiotic relationship with a white dwarf. Similar emissions were observed in 1965, 1967, 1977, 1992, and 1998. [9] The system was briefly thought to contain a third star [10] but this was later disproved. [6]
In 1984 bipolar jets were detected coming from CH Cygni, which were suspected to be due to accretion from its companion star. [9] [8] The luminosity of the system decreased significantly in 1986, likely owing to dust thrown out of the system by the jets or a concurrent helium flash. This dust had dissipated by 2002, with subsequent luminosities returning to pre-1985 levels. [3]
W Sagittarii is a multiple star system star in the constellation Sagittarius, and a Cepheid variable star.
Rho Leonis is a binary star in the zodiac constellation of Leo, and, like the prominent nearby star Regulus, is near the ecliptic. With an apparent visual magnitude of 3.9, this star can be readily seen with the naked eye. Parallax measurements give a distance estimate of about 5,400 light-years from the Earth. Rho Leonis is an Alpha Cygni-type variable star, showing 0.032 magnitude brightness variations with a period of 3.427 days, in Hipparcos data.
Z Andromedae is a binary star system consisting of a red giant and a white dwarf. It is the prototype of a type of cataclysmic variable star known as symbiotic variable stars or simply Z Andromedae variables. The brightness of those stars vary over time, showing a quiescent, more stable phase and then an active one with a more pronounced variability and stronger brightening and/or dimming.
R Aquarii is a variable star in the constellation Aquarius.
S Normae is a yellow supergiant variable star in the constellation Norma. It is the brightest member of the open cluster NGC 6087.
S Monocerotis, also known as 15 Monocerotis, is a massive multiple and variable star system located in the constellation Monoceros. It is the brightest star in the Christmas Tree open cluster in the area catalogued as NGC 2264.
SS Cygni is a variable star in the northern constellation Cygnus. It was discovered in 1896 by Louisa D. Wells, a computer working under Edward Pickering at Harvard College Observatory. It is the prototype of the subclass of dwarf novae that show only normal eruptions. It typically rises from 12th magnitude to 8th magnitude for 1–2 days every 7 or 8 weeks. The northerly declination of SS Cygni makes the star almost circumpolar from European and North American latitudes, allowing a large proportion of the world's amateur astronomers to monitor its behavior. Furthermore, since the star lies against the rich backdrop of the Milky Way band, the telescope field of view around SS Cygni contains an abundance of useful brightness comparison stars.
55 Cygni is a blue supergiant star in the constellation Cygnus. It is thought to be a member of the Cygnus OB7 stellar association at about 2,700 light years.
9 Cephei, also known as V337 Cephei, is a variable star in the constellation Cepheus.
Gamma Phoenicis is a star system in the constellation Phoenix, located around 71.63 parsecs (233.6 ly) distant.
AH Scorpii is a red supergiant variable star located in the constellation Scorpius. It is one of the largest stars known by radius and is also one of the most luminous red supergiant stars in the Milky Way.
9 Persei is a single variable star in the northern constellation Perseus, located around 4,300 light years away from the Sun. It has the Bayer designation i Persei; 9 Persei is the Flamsteed designation. This body is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of about 5.2. It is moving closer to the Sun with a heliocentric radial velocity of −15.2 km/s. The star is a member of the Perseus OB1 association of co-moving stars.
42 Persei is a binary star system in the northern constellation of Perseus. It has the Bayer designation n Persei, while 42 Persei is the Flamsteed designation. The system is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.11. It is located around 93 parsecs (302 ly) distant from the Sun, but is drifting closer with a radial velocity of −12.4 km/s.
W Cygni is a semi-regular variable star in the constellation Cygnus, located 570 light-years from Earth. It lies less than half a degree southeast of ρ Cygni. W Cygni is, at times, a naked-eye star but it was not given a Bayer or Flamsteed designation. It has been proposed as a binary star system with a hotter main sequence companion, but this has not been confirmed.
SY Muscae is a binary star system in the constellation Musca composed of a red giant and a white dwarf. Its apparent magnitude varies from 10.2 to 12.7 over a period of 624.5 days. Although the binary is a symbiotic star system, it is unusual in that it does not have an eruptive component. It is an S-type symbiotic system, which means that the light comes from the stars rather than surrounding dust.
HD 87643 is a B[e] class binary star embedded in a reflection nebula.
BC Cygni is a red supergiant and pulsating variable star of spectral type M3.5Ia in the constellation Cygnus.
RW Cygni is a semiregular variable star in the constellation Cygnus, about a degree east of 2nd magnitude γ Cygni. Its apparent magnitude varies between 8.05 and 9.70 and its spectral type between M3 and M4.
BI Cygni(BI Cyg, IRC +40408, BD+36 4025) is a red supergiant in the constellation Cygnus. It is an irregular variable star with a maximum brightness of magnitude 8.4 and a minimum of magnitude 9.9. It is considered a member of the stellar Cygnus OB1 association, its distance is around 2,600 parsecs (8,500 ly) of the Solar System. It is less than a degree south of another variable red supergiant, BC Cygni.
S Cassiopeiae is a Mira variable and S-type star in the constellation Cassiopeia. It is an unusually cool star, rapidly losing mass and surrounded by dense gas and dust producing masers.